It is generally known that an internal combustion engine for motor vehicles is equipped with a catalytic converter for emission control. It is also known such engines may also be provided with variable valve overlap between inlet and exhaust valves. By temporarily increasing the valve overlap, a performance of the internal combustion engine can be increased if required.
In the process, an oxygen quantity in the exhaust gas and thus in the catalytic converter can increase in particular through the temporary increasing of the valve overlap. However, when an oxygen quantity in the catalytic converter is too high, a reduction of nitrogen oxides (NOx) in the catalytic converter can deteriorate when a corresponding oxygen quantity is already present or stored in the catalytic converter. According there is a need to improve an internal combustion engine to address this issue.